The present invention relates to a revolving turret in general, and more particularly to an indexable revolving turret.
Still more specifically, the invention relates to an automatically indexing revolving turret, such as is used in tool machines.
It is known from German published application No. OS 2,103,741 to provide an indexable revolving turret having annular spur gears which effect the indexing of the turret. From this application it is also known to disengage the tool carrier of the turret from the annular spur gears provided for the indexing function, by means of a drive screw which is associated with a very complicated mechanical transmission having a large number of parts. This is required in order to be able to index the tool carrier after disengaging the annular spur gear provided on the tool carrier from the annular spur gear provided on the housing of the turret. The indexing positions are sensed by limit switches.
This prior-art construction provides for an exact and satisfactory indexing operation. However, it is structurally very complicated and therefore expensive and it requires a complicated control arrangement to provide an interlock against undesired movements. Also, the indexing movements are not as fast as is desirable.
Another type of indexable turret is known from German Pat. No. 969,332 in which the tool carrier is indexed (advanced) by a Maltese-cross drive. In this type of construction the indexing is based upon the snapping of a spring-loaded bolt or pin into appropriate recesses. It is then not necessary to move the tool carrier itself out of engagement, as in the preceding case where the engagement of spur gears on the tool carrier and on the housing must be temporarily interrupted. However, the use of such spring-loaded bolts or pins has the drawback that when the equipment is subjected to rough usage the indexing reliability is no longer as good as it should be, and particularly over a prolonged period of use the indexing accuracy will not be as effective as when spur gears are used.